Microsoft rules out backward compatibility on Xbox One

Xbox 360 games are unlikely to work on the Xbox One, because Microsoft said that it would be ‘really problematic’ to do that

From Fudzilla:

Sony has promised that in the future it will offer PlayStation 3 games via its Gaikai cloud streaming service, but when and how this will work remains unclear. Redmond said that it is just too hard. According to Microsoft’s Albert Penello though the Xbox One doesn’t have a bats chance in hell, and seems to think that Gaikai wouldn’t work on PlayStation 4 either.